on wednesday president obama and mitt romney will face-off. both camps are trying to down play expectations. >> reporter: president obama is in nevada working to secure votes in the battleground state. >> hello las vegas. >> reporter: one of nine must win states and polls show a tight race. >> if you stand with me and work with me we will win again. we will win nevada again. we will win this election again. >>> the president is spending the next couple days cramming for the first of three debates. >> i know folks in the media are speculating on who will have the best zingers. mitt romney is a good debater. i am just okay. >> reporter: mitt romney began practicing in june and continued prepping tuesday. chris christie said mitt romney's performance will turn the race upside down. >> you will say we have a barn burner now. >> reporter: mitt romney's run -- paul ryan dialed back expectations. >> i don't think one event is going to make or break the campaign. >> reporter: paul ryan says mitt romney will lay out the choice voters have, especially w